The present invention relates generally to a process for the production of a cushion element, and apparatus for carrying out such a process.
In the context of this specification, such a cushion element may be for example but without limitation in respect thereof, in the form of the body portion of a head support or headrest for the back part of a seat, for example a motor vehicle seat, or the backrest portion or the squab or seat portion of such a seat.
In one form of a process for the production of a cushion element using a closable casting mold in which a plastic reaction mixture is caused to foam to produce the body portion of the cushion element, a piece of covering material which may be provided with a suitable lining is disposed on the mold and is drawn into contact with the internal surface defining the mold cavity by applying a vacuum thereto. The edge portions of the covering material project beyond the edge of the mold cavity. At the same time as the covering material is applied to the surface of the mold cavity, the mold is closed by means of a cover member and a reaction mixture is introduced into the closed mold. The reaction mixture may be for example a plastic material which, by the reaction of the mixture in the mold, foams up in the mold. The mixture, after conclusion of the reaction thereof in the mold, may produce a foam which is of a single defined level of hardness throughout, or a foam which comprises foams of different hardnesses in different regions thereof. After reaction of the mixture has occurred, the mold is opened, that is to say the cover member which closed the mold cavity is removed and the foamed cushion element which is provided with the covering material on the front side thereof is then removed from the mold. The projecting edge portions of the covering material are then trimmed off.
It will be noted that the rear side of the cushion element which is formed by the internal surface of the cover member closing the mold does not have any covering thereon. Therefore, after the edge portions of the covering material have been trimmed off, the cushion element needs to be subjected to a further processing operation to provide a cover on the rear side thereof. However, applying such a cover to the rear side of the cushion element, by virtue of involving an additional working operation, has an adverse effect on the cost of production of the cushion element.